使用FFMPEG5.0和SDL2.0编写视频简单播放器
作者：互联网
使用ffmpeg5.0和SDL1.2（操作系统原本安装了这个版本，所以想先用这个库调试看看），编写视频播放器daemon时，视频卡在第一帧会报错：
测试例程如下：
int B_Play_Openfile(const char* szFilePath)
{
int iRet = 0;
int iVideo_index = 0;
char szError[128] = {0};
unsigned char *out_buffer = NULL;
AVFormatContext *FormatContext = avformat_alloc_context(); /* 媒体文件句柄 */
AVCodec *Video_Codec = NULL; /* 解码器句柄 */
AVCodecContext *Video_CodecContext = NULL; /* 解码器上下文 */
AVFrame *Video_Frame = NULL; /* 帧缓存 */
AVFrame *YUV_Frame = NULL; /* YUV帧 */
AVPacket *Video_Packet = NULL;
if (szFilePath == NULL)
{
B_LOG("illegal file path\r\n");
return -1;
}
else
{
B_LOG("B_Play_Openfile, Path[%s]\r\n", szFilePath);
}
/* 打开一个输入流并读取头部 */
iRet = avformat_open_input(&FormatContext, szFilePath, NULL, NULL);
if (iRet != 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avformat_open_input fail, Ret[%d], Err[%s]\r\n", iRet, szError);
return iRet;
}
/* 读取媒体文件的数据包以获取流信息 */
iRet = avformat_find_stream_info(FormatContext, NULL);
if (iRet < 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avformat_open_input fail, Ret[%d], Err[%s]\r\n", iRet, szError);
avformat_close_input(&FormatContext);
return iRet;
}
/* 查找视频码流索引 */
iVideo_index = av_find_best_stream(FormatContext, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
if (AVERROR_STREAM_NOT_FOUND == iVideo_index)
{
/* 未找到视频流 */
B_LOG("av_find_best_stream not found video stream\r\n");
avformat_close_input(&FormatContext);
return -1;
}
else if (AVERROR_DECODER_NOT_FOUND == iVideo_index)
{
/* 找到视频流，但是没找到解码器 */
B_LOG("av_find_best_stream streams were found but no decoder\r\n");
avformat_close_input(&FormatContext);
return -1;
}
/* 查找解码器 */
Video_Codec = avcodec_find_decoder(FormatContext->streams[iVideo_index]->codecpar->codec_id);
if (NULL == Video_Codec)
{
B_LOG("avcodec_find_decoder fail\r\n");
avformat_close_input(&FormatContext);
return -1;
}
/* 创建解码器上下文(为Video_CodecContext申请内存空间) */
Video_CodecContext = avcodec_alloc_context3(Video_Codec);
if (NULL == Video_CodecContext)
{
B_LOG("avcodec_alloc_context3 fail\r\n");
avformat_close_input(&FormatContext);
return -1;
}
/* 预初始化解码器上下文(从FormatContext->streams[iVideo_index]->codecpar获取解码器的有关参数,并填充至Video_CodecContext) */
iRet = avcodec_parameters_to_context(Video_CodecContext, FormatContext->streams[iVideo_index]->codecpar);
if (iRet < 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avcodec_parameters_to_context fail, Ret[%d], Err[%s]\r\n", iRet, szError);
avformat_close_input(&FormatContext);
return iRet;
}
/* 打开解码器上下文 */
iRet = avcodec_open2(Video_CodecContext, Video_Codec, NULL);
if (iRet != 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avcodec_open2 fail, Ret[%d], Err[%s]\r\n", iRet, szError);
avformat_close_input(&FormatContext);
return iRet;
}
/* 申请帧缓存 */
Video_Frame = av_frame_alloc();
if (NULL == Video_Frame)
{
B_LOG("av_frame_alloc fail,\r\n");
avformat_close_input(&FormatContext);
return iRet;
}
YUV_Frame = av_frame_alloc();
if (NULL == YUV_Frame)
{
B_LOG("av_frame_alloc fail,\r\n");
avformat_close_input(&FormatContext);
return iRet;
}
struct SwsContext *img_convert_ctx;
int Video_H = 0; /* 视频高 */
int Video_W = 0; /* 视频宽 */
SDL_Surface *screen;
SDL_VideoInfo *vi;
SDL_Overlay *bmp;
SDL_Rect rect;
int got_picture;
iRet = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER);
if (iRet != 0)
{
B_LOG("SDL_Init fail, Ret[%d]\r\n", iRet);
avformat_close_input(&FormatContext);
return iRet;
}
Video_H = Video_CodecContext->width;
Video_W = Video_CodecContext->height;
screen = SDL_SetVideoMode(Video_W, Video_H, 0, 0);
if (screen == NULL)
{
B_LOG("SDL_SetVideoMode fail, Ret[%d]\r\n", iRet);
avformat_close_input(&FormatContext);
return iRet;
}
bmp = SDL_CreateYUVOverlay(Video_CodecContext->width, Video_CodecContext->height,SDL_YV12_OVERLAY, screen);
rect.x = 0;
rect.y = 0;
rect.w = Video_W;
rect.h = Video_H;
Video_Packet = (AVPacket *)av_malloc(sizeof(AVPacket));
av_dump_format(FormatContext, 0, szFilePath, 0);
SDL_WM_SetCaption("B_Play",NULL);
img_convert_ctx = sws_getContext(Video_CodecContext->width, Video_CodecContext->height, Video_CodecContext->pix_fmt,
Video_CodecContext->width, Video_CodecContext->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
B_LOG("1111111");
while(av_read_frame(FormatContext, Video_Packet)>=0)
{
B_LOG("2222222");
if(Video_Packet->stream_index==iVideo_index)
{
//Decode
avcodec_send_packet(Video_CodecContext, Video_Packet);
got_picture = avcodec_receive_frame(Video_CodecContext, Video_Frame);
if(got_picture)
{
SDL_LockYUVOverlay(bmp);
YUV_Frame->data[0]=bmp->pixels[0];
YUV_Frame->data[1]=bmp->pixels[2];
YUV_Frame->data[2]=bmp->pixels[1];
YUV_Frame->linesize[0]=bmp->pitches[0];
YUV_Frame->linesize[1]=bmp->pitches[2];
YUV_Frame->linesize[2]=bmp->pitches[1];
sws_scale(img_convert_ctx, (const uint8_t* const*)Video_Frame->data, Video_Frame->linesize, 0,
Video_CodecContext->height, YUV_Frame->data, YUV_Frame->linesize);
SDL_UnlockYUVOverlay(bmp);
SDL_DisplayYUVOverlay(bmp, &rect);
//Delay 40ms
SDL_Delay(40);
}
}
av_packet_unref(Video_Packet);
}
B_LOG("3333333333\n");
while (1)
{
B_LOG("4444444444\n");
avcodec_send_packet(Video_CodecContext, Video_Packet);
got_picture = avcodec_receive_frame(Video_CodecContext, Video_Frame);
if (got_picture)
break;
sws_scale(img_convert_ctx, (const uint8_t* const*)Video_Frame->data, Video_Frame->linesize, 0, Video_CodecContext->height, YUV_Frame->data, YUV_Frame->linesize);
SDL_LockYUVOverlay(bmp);
YUV_Frame->data[0]=bmp->pixels[0];
YUV_Frame->data[1]=bmp->pixels[2];
YUV_Frame->data[2]=bmp->pixels[1];
YUV_Frame->linesize[0]=bmp->pitches[0];
YUV_Frame->linesize[1]=bmp->pitches[2];
YUV_Frame->linesize[2]=bmp->pitches[1];
SDL_UnlockYUVOverlay(bmp);
SDL_DisplayYUVOverlay(bmp, &rect);
//Delay 40ms
SDL_Delay(40);
}
sws_freeContext(img_convert_ctx);
SDL_Quit();
//av_free(out_buffer);
av_free(YUV_Frame);
avcodec_close(Video_CodecContext);
avformat_close_input(&FormatContext);
return 0;
}
当时对这个问题的理解不是很深刻，不过上网查了一下资料发现别人FFMPEG高版本但是搭配SDL2.0使用的，于是想着先用SDL2.0试试看。不过后面发现这个报错原因是自己代码写的有点问题（avcodec_receive_frame的返回值判断上写反了导致处理视频帧处没有进入。。。）
安装SDL2.0：
sudo apt-get install libsdl2-2.0
sudo apt-get install libsdl2-dev
安装完成后重新编译工程，发现有这么多报错：
原因是SDL1.2和2.0接口发生了比较大的差异，具体可以参看：https://blog.csdn.net/chaoswiming/article/details/46788707
根据SDL2.0接口重新编码后，还是会有编译报错：
这种问题一般是和库版本或是编译配置有关，于是我重新下了一份SDL源码，编译了一边，并且在自己过程的makefille里面链上了静态库：
这个时候会有这种报错：
看来是编译存在问题，修改makefile：
最终解决了SDL2.0的编译问题。
最后调试例程如下：
int B_Play_Openfile(const char* szFilePath)
{
int iRet = 0;
int iVideo_index = 0;
char szError[128] = {0};
unsigned char *out_buffer = NULL;
AVFormatContext *FormatContext = avformat_alloc_context(); /* 濯掍綋鏂囦欢鍙ユ焺 */
AVCodec *Video_Codec = NULL; /* 瑙ｇ爜鍣ㄥ彞鏌?*/
AVCodecContext *Video_CodecContext = NULL; /* 瑙ｇ爜鍣ㄤ笂涓嬫枃 */
AVFrame *Video_Frame = NULL; /* 甯х紦瀛?*/
AVFrame *YUV_Frame = NULL; /* YUV甯?*/
AVPacket *Video_Packet = NULL;
int ret, got_picture;
if (szFilePath == NULL)
{
B_LOG("illegal file path\r\n");
return -1;
}
else
{
B_LOG(">>>>>>>>>>>>>>>>>>>>>>>>>>>B_Play_Openfile, Path[%s]\r\n", szFilePath);
}
/* 鎵撳紑涓€涓緭鍏ユ祦骞惰鍙栧ご閮?*/
iRet = avformat_open_input(&FormatContext, szFilePath, NULL, NULL);
if (iRet != 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avformat_open_input fail, Ret[%d], Err[%s]\r\n", iRet, szError);
return iRet;
}
/* 璇诲彇濯掍綋鏂囦欢鐨勬暟鎹寘浠ヨ幏鍙栨祦淇℃伅 */
iRet = avformat_find_stream_info(FormatContext, NULL);
if (iRet < 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avformat_open_input fail, Ret[%d], Err[%s]\r\n", iRet, szError);
avformat_close_input(&FormatContext);
return iRet;
}
/* 鏌ユ壘瑙嗛鐮佹祦绱㈠紩 */
iVideo_index = av_find_best_stream(FormatContext, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
if (AVERROR_STREAM_NOT_FOUND == iVideo_index)
{
/* 鏈壘鍒拌棰戞祦 */
B_LOG("av_find_best_stream not found video stream\r\n");
avformat_close_input(&FormatContext);
return -1;
}
else if (AVERROR_DECODER_NOT_FOUND == iVideo_index)
{
/* 鎵惧埌瑙嗛娴侊紝浣嗘槸娌℃壘鍒拌В鐮佸櫒 */
B_LOG("av_find_best_stream streams were found but no decoder\r\n");
avformat_close_input(&FormatContext);
return -1;
}
/* 鏌ユ壘瑙ｇ爜鍣?*/
Video_Codec = avcodec_find_decoder(FormatContext->streams[iVideo_index]->codecpar->codec_id);
if (NULL == Video_Codec)
{
B_LOG("avcodec_find_decoder fail\r\n");
avformat_close_input(&FormatContext);
return -1;
}
/* 鍒涘缓瑙ｇ爜鍣ㄤ笂涓嬫枃(涓篤ideo_CodecContext鐢宠鍐呭瓨绌洪棿) */
Video_CodecContext = avcodec_alloc_context3(Video_Codec);
if (NULL == Video_CodecContext)
{
B_LOG("avcodec_alloc_context3 fail\r\n");
avformat_close_input(&FormatContext);
return -1;
}
/* 棰勫垵濮嬪寲瑙ｇ爜鍣ㄤ笂涓嬫枃(浠嶧ormatContext->streams[iVideo_index]->codecpar鑾峰彇瑙ｇ爜鍣ㄧ殑鏈夊叧鍙傛暟,骞跺～鍏呰嚦Video_CodecContext) */
iRet = avcodec_parameters_to_context(Video_CodecContext, FormatContext->streams[iVideo_index]->codecpar);
if (iRet < 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avcodec_parameters_to_context fail, Ret[%d], Err[%s]\r\n", iRet, szError);
avformat_close_input(&FormatContext);
return iRet;
}
/* 鎵撳紑瑙ｇ爜鍣ㄤ笂涓嬫枃 */
iRet = avcodec_open2(Video_CodecContext, Video_Codec, NULL);
if (iRet != 0)
{
av_strerror(iRet, szError, sizeof(szError));
B_LOG("avcodec_open2 fail, Ret[%d], Err[%s]\r\n", iRet, szError);
avformat_close_input(&FormatContext);
return iRet;
}
/* 鐢宠甯х紦瀛?*/
Video_Frame = av_frame_alloc();
if (NULL == Video_Frame)
{
B_LOG("av_frame_alloc fail,\r\n");
avformat_close_input(&FormatContext);
return iRet;
}
YUV_Frame = av_frame_alloc();
if (NULL == YUV_Frame)
{
B_LOG("av_frame_alloc fail,\r\n");
avformat_close_input(&FormatContext);
return iRet;
}
#ifdef SDL2_0
int Video_H = 0; /* 瑙嗛楂?*/
int Video_W = 0;
out_buffer=(unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, Video_CodecContext->width, Video_CodecContext->height,1));
if (NULL == out_buffer)
{
B_LOG("av_malloc fail,\r\n");
avformat_close_input(&FormatContext);
return iRet;
}
struct SwsContext *img_convert_ctx;
av_image_fill_arrays(YUV_Frame->data, YUV_Frame->linesize,out_buffer, AV_PIX_FMT_YUV420P,Video_CodecContext->width, Video_CodecContext->height,1);
Video_Packet = (AVPacket *)av_malloc(sizeof(AVPacket));
av_dump_format(FormatContext, 0, szFilePath, 0);
img_convert_ctx = sws_getContext(Video_CodecContext->width, Video_CodecContext->height, Video_CodecContext->pix_fmt,
Video_CodecContext->width, Video_CodecContext->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
iRet = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER);
if (iRet != 0)
{
B_LOG("SDL_Init fail, Ret[%d]\r\n", iRet);
avformat_close_input(&FormatContext);
return iRet;
}
Video_H = Video_CodecContext->width;
Video_W = Video_CodecContext->height;
SDL_Window *screen = SDL_CreateWindow("B_Play", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, Video_W, Video_H, SDL_WINDOW_OPENGL);
if(!screen)
{
B_LOG("SDL: could not create window - exiting:%s\n",SDL_GetError());
return -1;
}
SDL_Renderer *sdlRenderer = SDL_CreateRenderer(screen, -1, 0);
SDL_Texture *sdlTexture = SDL_CreateTexture(sdlRenderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING,Video_CodecContext->width,Video_CodecContext->height);
SDL_Rect sdlRect;
sdlRect.x=0;
sdlRect.y=0;
//sdlRect.w=screen_w;
//sdlRect.h=screen_h;
sdlRect.w=500;
sdlRect.h=800;
while(av_read_frame(FormatContext, Video_Packet)>=0){
if(Video_Packet->stream_index==iVideo_index){
//iRet = avcodec_decode_video2(Video_CodecContext, Video_Frame, &got_picture, Video_Packet);
avcodec_send_packet(Video_CodecContext, Video_Packet);
got_picture = avcodec_receive_frame(Video_CodecContext, Video_Frame);
if(got_picture){
sws_scale(img_convert_ctx, (const unsigned char* const*)Video_Frame->data, Video_Frame->linesize, 0, Video_CodecContext->height, YUV_Frame->data, YUV_Frame->linesize);
SDL_UpdateYUVTexture(sdlTexture, &sdlRect,
YUV_Frame->data[0], YUV_Frame->linesize[0],
YUV_Frame->data[1], YUV_Frame->linesize[1],
YUV_Frame->data[2], YUV_Frame->linesize[2]);
SDL_RenderClear( sdlRenderer );
SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, &sdlRect);
SDL_RenderPresent( sdlRenderer );
SDL_Delay(40);
}
}
av_packet_unref(Video_Packet);
}
while (1) {
//ret = avcodec_decode_video2(Video_CodecContext, Video_Frame, &got_picture, Video_Packet);
avcodec_send_packet(Video_CodecContext, Video_Packet);
got_picture = avcodec_receive_frame(Video_CodecContext, Video_Frame);
if (got_picture)
break;
sws_scale(img_convert_ctx, (const unsigned char* const*)Video_Frame->data, Video_Frame->linesize, 0, Video_CodecContext->height,
YUV_Frame->data, YUV_Frame->linesize);
SDL_UpdateTexture( sdlTexture, &sdlRect, YUV_Frame->data[0], YUV_Frame->linesize[0] );
SDL_RenderClear( sdlRenderer );
SDL_RenderCopy( sdlRenderer, sdlTexture, NULL, &sdlRect);
SDL_RenderPresent( sdlRenderer );
SDL_Delay(40);
}
sws_freeContext(img_convert_ctx);
SDL_Quit();
av_frame_free(&YUV_Frame);
av_frame_free(&Video_Frame);
avcodec_close(Video_CodecContext);
avformat_close_input(&FormatContext);
#else
struct SwsContext *img_convert_ctx;
int Video_H = 0; /* 瑙嗛楂?*/
int Video_W = 0; /* 瑙嗛瀹?*/
SDL_Surface *screen;
SDL_VideoInfo *vi;
SDL_Overlay *bmp;
SDL_Rect rect;
int got_picture;
iRet = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER);
if (iRet != 0)
{
B_LOG("SDL_Init fail, Ret[%d]\r\n", iRet);
avformat_close_input(&FormatContext);
return iRet;
}
Video_H = Video_CodecContext->width;
Video_W = Video_CodecContext->height;
screen = SDL_SetVideoMode(Video_W, Video_H, 0, 0);
if (screen == NULL)
{
B_LOG("SDL_SetVideoMode fail, Ret[%d]\r\n", iRet);
avformat_close_input(&FormatContext);
return iRet;
}
bmp = SDL_CreateYUVOverlay(Video_CodecContext->width, Video_CodecContext->height,SDL_YV12_OVERLAY, screen);
rect.x = 0;
rect.y = 0;
rect.w = Video_W;
rect.h = Video_H;
Video_Packet = (AVPacket *)av_malloc(sizeof(AVPacket));
av_dump_format(FormatContext, 0, szFilePath, 0);
SDL_WM_SetCaption("B_Play",NULL);
img_convert_ctx = sws_getContext(Video_CodecContext->width, Video_CodecContext->height, Video_CodecContext->pix_fmt,
Video_CodecContext->width, Video_CodecContext->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
B_LOG("1111111");
while(av_read_frame(FormatContext, Video_Packet)>=0)
{
B_LOG("2222222");
if(Video_Packet->stream_index==iVideo_index)
{
//Decode
avcodec_send_packet(Video_CodecContext, Video_Packet);
got_picture = avcodec_receive_frame(Video_CodecContext, Video_Frame);
if(got_picture)
{
SDL_LockYUVOverlay(bmp);
YUV_Frame->data[0]=bmp->pixels[0];
YUV_Frame->data[1]=bmp->pixels[2];
YUV_Frame->data[2]=bmp->pixels[1];
YUV_Frame->linesize[0]=bmp->pitches[0];
YUV_Frame->linesize[1]=bmp->pitches[2];
YUV_Frame->linesize[2]=bmp->pitches[1];
sws_scale(img_convert_ctx, (const uint8_t* const*)Video_Frame->data, Video_Frame->linesize, 0,
Video_CodecContext->height, YUV_Frame->data, YUV_Frame->linesize);
SDL_UnlockYUVOverlay(bmp);
SDL_DisplayYUVOverlay(bmp, &rect);
//Delay 40ms
SDL_Delay(40);
}
}
av_packet_unref(Video_Packet);
}
B_LOG("3333333333\n");
while (1)
{
B_LOG("4444444444\n");
avcodec_send_packet(Video_CodecContext, Video_Packet);
got_picture = avcodec_receive_frame(Video_CodecContext, Video_Frame);
if (got_picture)
break;
sws_scale(img_convert_ctx, (const uint8_t* const*)Video_Frame->data, Video_Frame->linesize, 0, Video_CodecContext->height, YUV_Frame->data, YUV_Frame->linesize);
SDL_LockYUVOverlay(bmp);
YUV_Frame->data[0]=bmp->pixels[0];
YUV_Frame->data[1]=bmp->pixels[2];
YUV_Frame->data[2]=bmp->pixels[1];
YUV_Frame->linesize[0]=bmp->pitches[0];
YUV_Frame->linesize[1]=bmp->pitches[2];
YUV_Frame->linesize[2]=bmp->pitches[1];
SDL_UnlockYUVOverlay(bmp);
SDL_DisplayYUVOverlay(bmp, &rect);
//Delay 40ms
SDL_Delay(40);
}
sws_freeContext(img_convert_ctx);
SDL_Quit();
//av_free(out_buffer);
av_free(YUV_Frame);
avcodec_close(Video_CodecContext);
avformat_close_input(&FormatContext);
#endif
return 0;
}
运行进程时发现出来的窗口是一片绿色的：
后面检查了一下代码，问题出在avcodec_receive_frame这个接口上面，通过查看注释发现，该接口成功获取到帧后返回值置为0，测试例程这个地方写反了
后面将if (got_picture)改成if (!got_picture)后视频流可以成功推送到屏幕上，不过示还存在一点问题，明天再研究一下：
标签：播放器,SDL2.0,Frame,YUV,CodecContext,Video,FFMPEG5.0,SDL,iRet 来源： https://blog.csdn.net/qq_45987579/article/details/120603728